In the plastic molding industry, injection molding presses are commonly charged with plastic particles from an overhead hopper. The raw plastic particles are generally shipped in cylindrical drums or in large boxes of the type referred to in the trade as Gaylords, and the plastic particles are transferred from the shipping containers to the press hoppers by means of vacuum loaders which include a suction tube adapted to extend into the container from which the plastic particles are to be removed.
In accordance with the prior art practice of using such vacuum loaders, the cover is first removed from the shipping container and the suction tube is pushed a short distance down into the mass of plastic pellets. Thereafter as the plastic pellets are removed and the level of the pellets in the container drops, the press operator pushes the suction tube farther down into the mass of plastic particles, and because the level does not ordinarily drop uniformly, the operator must also reposition the tube.
During the transfer operation, the plastic particles are exposed to the ambient and may, therefore, be contaminated. For example, water and oil in the air can adversely affect the subsequent molding operations, and foreign materials may get into the container because of carelessness or for other reasons. Not only is the plastic material expensive, wherefor such contamination is costly, but where, for example, the molded parts are used for packaging pharmaceutical products, such contamination can be hazardous.